Enhanced control scheme for grid-integrated photovoltaic inverter with wind-driven induction generator feeding unbalanced non-linear load

摘要

In this paper a composite power control design comprising of both voltage oriented control and direct power control (DPC) is developed for the grid-combined scheme based on photovoltaic array excited wind driven induction generator with unbalanced non-linear load (UNL) at the point of common coupling (PCC). The control and design strategy of the developed controller aims at control of instantaneous active and reactive power exchanged with the grid and suppression of the power oscillating terms that appear due to interaction between the different voltage and current sequences. When an induction generator feeds a non-linear load, de-rating of machine occurs and an attempt is made to reduce induction machine de-rating factor due to UNL with proposed control. Exhaustive simulations have been carried out with UNL at the PCC with varying wind speed and irradiation in grid-connected mode. The results are compared with existing DPC scheme. The proposed controller is also tested in islanding mode with line to line fault and load rejection at the PCC. The feasibility of incorporating the new developed control algorithm for grid-connected hybrid scheme is indicated in this work.